Ideally, yes - it allows for shortest, most direct ducting path outdoors (which is what we like!). But fans can be installed on any bathroom walls and ducted to ceiling vents or soffit vents. Extension ducting simply starts to reduce airflow. Our inline fan systems make up for this with brute strength and can be installed in various ways and yet still maintain great performance.
A qualified electrician, HVAC engineer or extractor fan specialists are the best choice for safely running wiring and ductwork. And, of course, us at Techmeisters limited are registered electricians who specialise in extractor fans and ventilation!